Large embroidery machines normally equipped with a few hundred embroidery locations which are arranged in one or more rows at equal intervals (embroidery location repeat). At each embroidery location, additional corresponding tools are associated with a needle (shuttle, borer, thread guide, thread supply, etc.). Operation with different embroidery location repeats (e.g. every second, third, etc. embroidery location), with differently colored yarns, or embroidery of any arrangement of patterns requires that certain embroidery locations are in use, but other embroidery locations are not working. For switching to different combinations of working and non-working embroidery locations, so-called color and repeat changing apparatuses have been developed.
Swiss patent 660 892 (Heinzle) shows a solution for switching the needles and borers between an embroidering and a non-embroidering state. The needles and borers are driven by a single shaft. This solution has the great disadvantage that every time there is a switch from embroidery to piercing and from piercing to embroidery, all the needles or borers must be uncoupled and all the borers or needles being used must be coupled. This connection of all needle couplings or borer couplings is repeated twice in each piercing process, even if work is being continued in the same repeat or in the same combination of embroidery locations. The result is, a large number of connections of all embroidery locations, particularly with pierced work. This results in a corresponding waste of time and energy.
By contrast, Swiss patent 651 081 (Comploi) shows a solution in which each needle and borer of all embroidery locations are driven by a separate shaft. With a single actuator per embroidery location, not only needle and borer, but also other tools of the embroidery location (thread supply, thread stop motion, etc.) are coupled. On switching from embroidery to piercing and vice versa, only the corresponding drive shaft is driven or stopped. Coupling or uncoupling of the tools of different embroidery locations takes place only on changing the combination of operative and inoperative embroidery locations. This solution requires a powerful actuator with corresponding power consumption, or power assist. As the tools of an embroidery location must be arranged separately, the solution with only one actuator (per embroidery location) requires corresponding mechanical connecting elements for coupling/uncoupling the different tools or restrictions in the arrangement of the tools.
In the above-mentioned previous solutions, when changing to a new combination of embroidering or non-embroidering embroidery locations, in each case all the embroidery locations must be brought to a basic state (e.g. all ON or all OFF), before a new combination can be switched. In the solution according to Swiss patent 660 892, all the needles or all the borers must be disconnected even with every switch from embroidery to piercing or piercing to embroidery.